SQL Server - Auto-incrementation that allows UPDATE statements

Question

When adding an item in my database, I need it to auto-determine the value for the field DisplayOrder. Identity (auto-increment) would be an ideal solution, but I need to be

Answer 1

Here's the solution that I kept:

CREATE PROCEDURE [dbo].[AddItem]

AS

DECLARE @DisplayOrder INT

BEGIN TRANSACTION

SET @DisplayOrder = (SELECT ISNULL(MAX(DisplayOrder), 0) FROM [dbo].[MyTable]) + 1

INSERT INTO [dbo].[MyTable] ( DisplayOrder ) VALUES ( @DisplayOrder )

COMMIT TRANSACTION